Mathematics
Grade10
Easy
Question
Find two numbers whose sum is 15 and difference is 3.
- 13 and 2
- 7 and 8
- 9 and 6
- 3 and 12
Hint:
Here we have to solve the system. Given equations are, x + y=15 and x − y=3. Use the basic concept and solve this question by substitution method.
The correct answer is: 9 and 6
Here we have to solve this equation,
Firstly, we have given, that the sum of the numbers is 15 that is
(Let the two numbers be x and y.)
x + y=15..........(1)
Also the difference of the numbers is 3 that is
x − y=3..........(2).
Add equations 1 and 2 to eliminate y, because the coefficients of y are opposite. So, we get
(x + x) + (y − y)=15+3
i.e. 2x = 18
⟹x=9
Substituting this value of x in (1), we get
9+y=15
i.e. y=15−9=6
Hence, the two numbers are 9 and 6.
In this question, we have to solve the equation, basically we have to find the value of x & y.
